Rock properties in low-porosity/low-permeability sandstones

摘要

Tight gas sand reservoirs are formally defined by the Federal Energy Regulatory Commission (FERC) as reservoirs with less than 0.1 md permeability. Although this is a permeability-based definition, these reservoirs frequently also have very low porosities (< 10%). Reservoirs that currently classify as "tight gas sands" account for approximately 19% of the total U.S. gas production and may contain upwards of 35% of the U.S. recoverable gas resources. In the U.S. Rockies alone, tight gas-sand reservoirs may contain upwards of 41.7 trillion cubic feet of gas; considerably more gas may exist in tight gas sand reservoirs at depths > 15 000 ft (Oil and Gas Investor, 2005).